Spinnable compositions comprising a fiber forming polyamide,a fiber forming polyester and a spinning aid



United States Patent 3,516,956 SPINNABLE COMPOSITIONS COMPRISING A FIBER FORMING POLYAMIDE, A FIBER IIIJRMING POLYESTER AND A SPINNING D Ora Lee Reedy, Richmond, Ian C. Twilley, Petersburg, and Norman B. Rainer, Richmond, Va., assignors to Allied Chemical Corporation, New York, N.Y., a corporation of New York No Drawing. Filed July 29, 1966, Ser. No. 568,725 Int. Cl. D01d N02 US. Cl. 260-22 18 Claims ABSTRACT OF THE DISCLOSURE Wax-like derivatives of saturated straight-chain carboxylic acids containing between about 12 and about 22 carbon atoms are incorporated into a spinnable composition comprising a fiber-forming polyamide having dispersed therein about to 50 percent by weight of a fiberforming polyester,. These wax-like derivatives (e.g., metallic salts, amides, and acylated hydrazines) have melting points above about 100 C. and mold release indices of greater than about 25 when incorporated into pure nylon-6. They are incorporated into the spinnable composition to the extent of between about 0.05 and about 0.6 percent 'by weight and serve to inhibit the formation of drips in the vicinity of spinneret o-rfices and reduce the occurrence of breaks or wraps during drawing of the spun filaments.

This invention relates to the preparation of textile fbers. More particularly, it relates to the preparation of fibers from compositions comprising polyesters dispersed in polyamides. It also includes within its scope the compositions themselves.

Spinnable compositions useful in the production of a \ariety of textile products including tire cords, drapes, rlothing and the like can be prepared by extruding melt l lended compositions comprising polyesters such as polyethylene terephthalate with polyamides especially nylons such as polycaproamide and polyhexamethylene adipamide. The filaments may be formed by first dry blending the polymers suitably in the form of chips and thereafter melt blending the compositions in a screw extruder or analogous device and extruding the molten composition through a spinnerette. @In the molten blend the polyester is dispersed in the polyamide in a fine state of subdivision. Such dispersion is normally attained by subjecting the melt to high shearin the extruder or analogous device and forcing the result melt through a pack of screens, a sand bed or similar fine filter. The molten dispersion is then extruded through the spinnerette into a cooling zone in which the extrudate solidifies in a filamentary form. The cooling one is normally a long stack in which the temperature and humidity are carefully controlled. There is a take-up roll for winding the filaments at the bottom of the stack.

The filaments are normally gathered together into yarns which may then be subjected to a drawing operation to improve their physical properties. The drawing operation is generally carried out by extending the yarns at a temperature below the melting point of either component of the yarns and confers molecular orientation along the filament axis so as to increase the strength of the yarns. Draw ratios of from about 3.5 to about 6.5 are normally employed with polyester-polyamide compositions, draw ratio being defined as the ratio of the length of the drawn yarn to the length of the undrawn yarn. Lower draw ratios within this range are used in the preparation of textile yarns where high strength is not necessarily a requirement. Higher dra w ratios within the range are usually used for the preparation of high strength yarns such as yarns intended for use in tire cords. The yarn can be. drawn in either single or successive stages and at least one of the stages is best carried out at a relatively high temperature. The drawing operation is preferably carried out with the aid of a drawpin which localizes the region of drawing.

At the end of the drawing operation the yarn is taken up on a take up roll or a pirn and is then ready for use.

If desired, the yarn may also be twisted to improve cohesion of the several filaments before use.

There are a number of difliculties in the above described operation which arise despite the most stringent precautions. Drips due to partial blockage of an orifice producing discontinuities in the filament at or just below the spinnerette face ii] a problem which has proved to be particularly troublesome in the spinning of filaments. The problem of drips in spinning polyester polyamide blends is particularly troublesome when one extruder is used as the melt blending apparatus to feed more than one spinnerette so as to utilize the extruder with maximum efficiency. It has proved especially difficult with polyesterpolyamide blends to increase production rates by this procedure. It has been observed in many instances that the operation of one position with one extruder is satisfactory, but there is excessive dripping when one or more other positions are associated with the same extruder.

Also, during the drawing operation, breaks or wraps may develop in the yarn. A break is the rupture of the yarn in the draw zone. This requires a shutdown and restarting of the entire drawing operation. A wrap occurs when one or more but less than all of the filaments in the yarn rupture in the draw zone. The oncoming ends of the ruptured filaments will wrap around the roll instead of moving ahead to the twister. This situation can sometimes be corrected without shutting down, but the properties of the resulting yarn may be adversely affected.

It has been observed in accordance with this invention that the above mentioned difficulties can be substantially alleviated by the provision of spinnable compositions in which up to about 50 parts of fiber forming polyester per parts of fiber composition are dispersed in a continuous body of fiber forming polyamide containing from about 0.05 to about 0.6 part by weight of at least one wax-like spinning aid having a melting point above 100 C. which may be further characterized as derivatives of straight chain saturated acyl compounds containing from about 12 to 22 carbon atoms in the hydrocarbon chain. The spinning aids employed in this invention have a mold release index of at least 25 when incorporated in pure nylon 6 (polycaprolactam or polycaproamide-, and they do not exert a plasticizing effect on the polyester-polyamide blend, more specifically, they do not reduce the tensile modulus of fibers prepared from the blend. Spinning aids having the desired characteristics are generally derivatives of long chain fatty aliphatic acids such as lauric, palmitic, stearic or behenic acid. Metallic salts, amides and acylated hydrazines are typical examples of useful spinning aids. The following table lists a number of representative wax-like spinning aids found to be useful in accordance with this invention together with their melting points and mold release indices. These representative wax-like spinning aids include diamides derived by the reaction of an aliphatic carboxylic acid and a diamine or hydrazine and alkali or alkaline earth metal salts of aliphatic carboxylic acids.

TABLE I Melting Mold point of release additive, index of Additive compound C. additive Ethylene bis stearamide [1,2-bis(stearamido)ethane] 143 40 CHa(CH2)1sCONHCHzCH2-NHCO(CH2)10CH3 Methylene bis stea1mide [bis(stearamido)methane]. 130 38 CHa(CH2)ieCONHCH2-N Ethylene bis behcnamide [1,2-bis(behenamide)ethane 134 42 CH3(CH2)2oCONHCH2CH2-NHCO(CHzhoCHa N,N (hydrazine) distearamide [N,N-bis(stearoly)hydrazidc] 132 40 CHa(CH2)1aCONHNHC0(CH2)1&CH3

p-Phenylene bis stearamide {IA-bis(stcaramido)benzene] I 167 65 engmnmoomr-Q-mrc o (CH2)16CH3 (1,4 phcnyl) stearate stearamide [l-stearateA-stearamido benzene]...

120 34 CH (CH2)1sCO OQ-NHC (OH2)1GCH3 (p,p' diphenyl other) dipalmitamide [p,p-bis(palmitamido)diphenyl ether] 181 29 CH3(CH2)14C ONHONHO 0(0119140113 (p,p diphcnyl methyl) distearamidc [p,p-bis(stearamido)diphenyhnethane] 162 37 CH;(CII2)1GC oNl-rcln-nnc o (011M011 (p,p diphenyl methyl) dilauramide [p,p-bis(lauramido)diphenylmcthanc] 171 33 CH3(CII2)111C0NH-CH2-NHC 0 ommom (p,p diphcnyl) distefiarlnidefi -bis stcarami o i ien [p p 1 y 223 42 0113 0119160 ouu@ mrc 0(CH:)1HCII3 Sodium stearate 200 42 Sodium pahnitate- 270 35 Barium stcarate. 145 33 Calcium stearate- 148 39 Copper stearate. 125 27 Lithium stearate. 215 40 Magnesium stearate. 159 38 Zinc stearato 125 32 In the test used to determine the mold release index of compounds useful in this invention, nylon 6 (polycaprolactam or polycaproamide) pellets containing, homogeneously blended therein, 0.2% of the additive to be tested are fed to a Van :Dorn injection molding machine operating at a rear cylinder temperature of 365 F. and a mold temperature of 180 F. The injection line pressure is maintained at 1100 psi. with an injection forward time of seconds and a mold open time of at least 2 seconds. The front cylinder temperature is adjusted to produce the melt viscosity required to fill the mold without flash, i.e., the filmy attachments to the edges of the molded article due to polymer leakage between the halves of the mold. The mold employed is a disk of 2 inches diameter and A; inch thickness provided with a inch diameter plunger flush-mounted in the bottom of the mold and centered therein. The mold is fabricated of Type 430 stainless steel. The melting time is 2 minutes, injection time seconds, and clamp time seconds. In testing for the mold release propensity of a composition, the force necessary to extricate the disk from its mold is measured via pneumatic pressure applied to the plunger. A comparative test is made on a control sample of the same polyamide containing no mold release additive.

The mold release index is defined as the percentage- Wise decrease in extrication pressure for the test sample in comparison with the control. For example, if the pure polyamide extrication pressure is 110 p.s.i.g. and the extrication pressure of the sample being tested is 60, then the mold release index would be 11060/110 :45. By this test method, spinning aids which are useful in the present invention will have to have a mold release index greater than 25.

In carrying out the test, temperatures, pressures, and residence times are observed and recorded to assure consistency and reproducibility of results. At the beginning of each series of tests, the molding machine is purged with standard pure polyamide polymer. Then the system is purged (usually 20-30 shots) with the polymer under test until uniform results are obtained. During this period, optimum operating temperatures and injection pressure are determined. After purging, the extrication pressures from 10 consecutive moldings are averaged and recorded as the extrication pressure for the polymer/ additive composition.

The preferred spinning aids are alkali and alkaline earth metal salts since these compounds are readily and economically available in substantially pure form. Sodium palmitate and sodium stearate are particularly preferred because of the excellent results which can be obtained by their use.

The selected spinning aid can be added at any con venient time during the dry or melt blending of the composition or may be incorporated in the polymers during polymerization. It may be added in solid form or in a solution or slurry employing a low boiling liquid which may be removed by evaporation. In the presently preferred procedure, a Spinning aid in solid particulate form is mixed with the fiber forming polymer components during the dry blending. It is simply added to the dry, particulate blend and the whole mass mixed by stirring or other suitable means. During the mixing the spinning aid is evenly distributed on the surfaces of the polymer particles, thereby assuring its uniform distribution throughout the polymer composition.

Useful results can be achieved in accordance with this invention with compositions containing as little as parts by weight of polyester or even less. However, the difliculties outlined above become progressively more troublesome with increasing concentration of polyester. Accordingly, the invention is especially useful with compositions in which the polyester content is 30 parts by weight or higher.

In an especially preferred embodiment of the invention a spinning aid is used in association with the fiber forming polyester-polyamide compositions described and claimed in copending patent application Ser. No. 368,028 filed on May 18, 1964, Now U.S. Pat. No. 3,369,057, issued Feb. 13, 1968, which is assigned to the same assignee as this application. That application describes filament-forming compositions comprising from about to about 50 parts by weight of filament-forming polyester dispersed as microfibers in a continuous body of from about 50 to about 90 parts by weight of filament-forming polyamide. The polyamide is further characterized as having not more than 40% end group species which are reactive with the polyester in the melt. The polyester is a long chain polymeric ester having a glass transition temperature when in the amorphous form which is at least 50 C. as measured by differential thermal-analysis and is higher than that of the polyamide component. The reduced viscosity of the polyamide component as measured at a concentration of 0.5 gram of polymer per 100 milliliter of solution in ortho-chlorophenol at 25 C. is in the range of 0.9 to 1.4 and the ratio of polyamide reduced viscosity to polyester reduced viscosity is between about 0.9 and 2.0. The composition is generally melt blended and extruded through the spinnerette at a temperature of from about 260 C. to about 285 C. which is about 10 C. to 40 C. above the melting point of the higher melting component.

Polycaproamides and polyhexamethylene adipamides are utilized in preferred embodiments of this invention, although other polyamides prepared from polyamides forming monomers containing from 4 to 14 carbon atoms may be employed. Preferred polyesters include the polyethylene phthalates especially polyethylene terephthalates although other condensation products of dibasic acids such as naphthalene-2,6, and 2,7 dicarboxylic acids, and polyhydroxy alcohols such as ethylene or propylene glycol, or sterically hindered glycols maybe employed.

The following examples are given by way of illustration only and should not be considered as limitations of this invention, many apparent variations of which are possible without departing from the spirit or scope thereof.

6 EXAMPLE 1 Pellets of polyethylene terephthalate having the following properties were employed:

Melting point, C. (differential thermal analysis) 252 End group analysis in milliequivalents per kilogram of polymer carboxyl 55 Hydroxyl 65 Reduced viscosity in orthochlorophenol 0.80 Glass transition temperature, C. (differential thermal analysis) 58 Pellets of polycaproamide having the following properties were employed:

Melting point, C. (differential thermal analysis 222 End group analysis is milliequivalents per kilogram of polymer carboxyl 72 Amino 10 Reduced viscosity in orthochlorophenol 1.13 Glass transition temperature, C. (differential thermal analysis) 48 A mixture of 55 parts polyamide and 45 parts polyester pellets by weight was blended in a tumble blender for one hour. The granular blend was dried to a moisture content of no more than .07% and then melt blended at 279 C. in a 3 /2 inch diameter extruder operated at a rotational speed of about 23.1 r.p.m. to produce a pressure of about 3800 lbs. per square inch at the outlet. The temperature of the polymer composition on leaving the extruder was 279 C.

The molten mixture was pumped through a filter pack including a series of screens and a sand bed under a pressure of 2800 lbs. per square inch at a temperature of 265 C. and was extruded through a spinnerette plate having 204 orifices of circular cross section each of said orifices having the following dimensions-length 0.069 inch, diameter 0.018 inch, entrance angle 60". The resulting filaments passed downwardly through a quenching chamber containing air at 27.8 C. and 65% relative humidity flowing concurrently to the filaments at a rate of about 75 cubic feet per minute. The yarn was taken up onto a cylindrical package below the quenching chamber at a speed of 1140 feet per minute under a tension of 35 grams. Just prior to packaging a lubricating finish was applied to the yarn to the extent of 4.3% pickup based on the weight of yarn. The yarn thus obtained has an approximate denier of 6772 and a birefringence of 0.004.

The yarn was then subjected to a drawing operation by running the yarn to an upper draw roll from a cot feed roll. It was then passed in one wrap about a stationary ceramic drawpin of 1% inch diameter to a contact surface heater at C. and finally in 5 wraps about a lower draw roll at a peripheral speed of 5.52 times faster than the upper draw roll. The yarn was drawn to 5.3 times its initial length.

The yarn was subsequently wound onto a pirn at a rate of 840 feet per minute using a ring-traveler device so as to impart 0.5 turn per inch twist to the yarn. The yarn thus obtained has the following properties:

Denier 1279 Ultimate elongation, percent 14.7 Ultimate tensile strength, grams per denier 8.56

Breaking strength, grams 10,947 Tensile modulus, grams per denier 73 Shrinkage, percent 12 The following phenomena were observed during the preparation of 198 pounds of yarn:

EXAMPLE 2 The process of this example is substantially similar to that of Example 1. Comparison of the two examples 7 clearly establishes the superiority of spinning composition containing sodium stearate.

Pellets of polyethylene terephthalate having the following properties were employed:

Melting point C. (differential thermal-analysis) 252 End group analysis in milli-equivalents per kilogram of polymer carboxyl 55 Hydroxyl 65 Reduced viscosity in orthochlorophenol 0.80 Glass transition temperature, C. (differential thermal-analysis) 58 Pellets of polycaproamide having the following properties were employed:

Melting point, C. (differential thermal-analysis) 222 End group analysis in milli-equivalents per kilogram of polymer carboxyl 73 Amino 18 Reduced viscosity in ortho-chlorophenol 1.10 Glass transition temperature, C. (differential thermal-analysis) 48 The mixture of 55 parts polyamide and 45 parts polyester pellets by weight was blended together with 0.2 part by weight of sodium stearate dry powder in a tumble blender for one hour. The granular blend was dried to a moisture content of less than 0.07% and then melt blended to about 278 C. in a 3 /2 inch diameter extruder operated at a rotational speed of about 25 r.p.m. to produce a pressure of about 3500 lbs. per square inch at the outlet. The temperature of the polymer composition on leaving the extruder was 278 C.

The molten mixture was pumped through a filter pack including a series of screens and a sand bed under a pressure of 3500 lbs. per square inch at a temperature of 265 C. and was extruded through a spinnerette plate having 204 orifices of circular cross section each of said orifices having the following dimensionslength 0.069 inch, diameter 0.018 inch, entrance angle 60. The resulting filaments passed downwardly through a quenching chamber containing air at 27.8" C. and 65% relative humidity flowing cocurrently to the filaments at a rate of about 75 cubic feet per minute. The yarn was taken up onto a cylindrical package below the quenching chamber at a speed of 1178 feet per minute under a tension of 35 grams. Just prior to packaging a lubricating finish was applied to the yarn to the extent of 4.5% pickup based on the weight of yarn. The yarn thus obtained had an approximate denier of 6727 and a birefringence of 0.003.

The yarn was then subject to a drawing operation by running the yarn to an upper draw roll from a cot feed roll. It was then passed in one wrap about a stationary ceramic drawpin of 1 /2 inch diameter to a contact surface heater of 185 C. and finally in 5 wraps about a lower draw roll at a peripheral speed of 5.58 times faster than the upper draw roll. The yarn was drawn to 5.38 times its initial length.

The yarn was subsequently wound onto a pirn at a rate of 840 feet per minute using a ring-traveler device so as to impart 0.5 turn per inch twist to the yarn. The yarn thus obtained had the following properties:

Denier 1257 Ultimate Elongation, percent 15.6 Ultimate tensile strength, grams per denier 8.67

Breaking strength, grams 10,892 Tensile modulus, grams per denier 77 Shrinkage percent 12 The following phenomena was observed during the preparation of 196 pounds of yarn:

Drips per hour at the spinnerette 0.47 Breaks per pound at the drawtwister 0.010 Wraps per pound at the drawtwister 0.020

8 EXAMPLE 3 Pellets of polyethylene terephthalate having the following properties were employed:

Melting point, C. (differential thermal-analysis) 252 End group analysis in milli-equivalents per kilogram of polymer carboxyl 55 Hydroxyl 65 Reduced viscosity in ortho-chlorophenol 0.80 Glass transition temperature, C. (differential thermal-analysis) 58 Pellets of polycaproamide having the following properties were employed:

Melting point, C. (differential thermal-analysis) 222 End group analysis in milli-equivalent per kilogram of polymer carboxyl 71 Amino 13 Reduced viscosity in ortho-chlorophenol 1.0 Glass transistor temperature, C. (differential thermal-analysis) 45 A mixture of 55 parts polyamide and 45 parts polyester pellets by weight was blended in a tumble blender for one hour. The granular blend was dried to a moisture content of no more than 039% and then melt blended at 275 C. in a 3 /2 inch diameter extruder operated at a rotational speed of about 23.5 r.p.m. to produce a pressure of about 3000 lbs. per square inch at the outlet. The temperature of the polymer composition on leaving the extruder was 275 C.

The molten mixture was pumped through a filter pack including a series of screens and a sand bed under a pressure of 2900 lbs. per square inch at a temperature of 265 C. and was extruded through a spinnerette plate having 204 orifices of circular cross section each of said orifices having the following dimensionslength 0.069 inch, diameter 0.018 inch, entrance angle 20. The resulting filaments passed downwardly through a quenching chamber containing air at 27.80 C. and 65% relative humidity flowing cocurrently to the filaments at a rate of about 75 cubic feet per minute. The yarn was taken up onto a cylindrical package below the quenching chamber at a speed of 1180 feet per minute under a tension of 35 grams. Just prior to packaging a lubricating finish was applied to the yarn to the extent of 4.4% pickup based on the weight of yarn. The yarn thus obtained had an approximate denier of 6712 and a birefringence of 0.00228.

The yarn was then subjected to a drawing operating by running the yarn to an upper draw roll from a cot feed roll. It was then passed in one wrap about a stationary ceramic drawpin of 1 /2 inch diameter to a contact surface heater at C. and finally in 5 wraps about a lower draw roll at a peripheral speed of 5.58 times its initial length.

The yarn was subsequently wound onto a pirn at a rate of 840 feet per minute using a ring-traveler device so as to impart 0.5 turn per inch twist to the yarn. The yarn thus obtained had the following properties:

Breaking strength, grams 10,458 Tensile modulus, grams per denier 84 Shrinkage, percent 11 The following phenomena were observed during the preparation of 87 pounds of yarn:

Drips per hour at the spinnertte 3.0 Breaks per pound at the drawtwister 0.046 Wraps per pound at the drawtwister 0.368

EXAMPLE 4 The process of this example is substantially similar to that of Example 3. Comparison of the results of the two examples clearly establishes the superiority of spinning compositions containing sodium palmitate.

Pellets of polycaproamide having the following properties were employed:

Melting point, C. (dilferential thermal-analysis) 222 End group analysis in milli-equivalents per kilogram of polymer carboxyl 79 Amino 13 Reduced viscosity in orthochlorophenol 1.0 Glass transition temperature, C. (differential thermal-analysis) 45 The mixture of 55 parts polyamide and 45 parts polyester pellets by weight was blended together with 0.1 part by weight of sodium palmitate dry powder in a tumble blender for one hour. The granular blend was dried to a moisture content of no more than 0.039% and then melt blended at 275 C. in a 3 /2 inch diameter extruder operated at a rotational speed of about 26 r.p.m. to produce a pressure of about 2900 lbs. per square inch at the outlet. The temperature of the polymer composition on leaving the extruder was 275 C.

The molten mixture was pumped through a filter pack including a series of screens and a sand bed under a pressure of 2300 lbs. per squareinch at a temperature of 275 C. and was extruded through a spinnerette plate having 204 orifices of circular cross section each of said orifices having the following dimensions-length 0.069 inch, diameter 0.018 inch, entrance angle 20. The resulting filaments passed downwardly through a quenching chamber containing air at 27 .8 C. and 65% relative humidity flowing cocurrently to the filaments at a rate of about "75 cubic .feet per minute. The yarn was taken up onto a cylindrical package below the quenching chamber at a speed of 1130 feet per minute under a tension of 35 grams. Just prior to packaging a lubricating finish was applied to the yarn to the extent of 4.5% pickup based on the weight of yarn. The yarn thus obtained had an approximate denier of 7026 and a birefringence of 0.0014.

The yarn was then subjected to a drawing operation by running the yarn to an upper draw roll from a cot feed roll. It was then passed in one wrap about a stationary ceramic drawpin of 1% inch diameter to a contact surface heater at 185 C; and finally in 5 wraps about a lower draw roll at a peripheral speed of 5.78 times faster than the upper draw roll the yarn drawn to 5.72 times its initial length.

The yarn was subsequently wound onto a pirn at a rate of 840 feet per minute using a ring-traveler device so as to impart 0.5 turn per inch twist to the yarn. The yarn thus obtained had the following properties:

Denier 1267 Ultimate elongation, percent 15.0 Ultimate tensile strength, grams per denier 8.2 Breaking strength, grams a. 10,38

Tensile modulus, gramsper denier 84 Shrinkage, percent The following phenomena were observed during the preparation of 111 pounds of yarn:

Drips per hour at the spinnerette 0.67 Breaks per pound at the drawtwister 0.054 Wraps per pound at'the drawtwister 0.054

10 EXAMPLE 5 Pellets of polyethylene terephthalate having the following properties were employed:

Melting point, C. (differential thermal-analysis) 250 End group analysis in milli-equivalents per kilogram of polymer carboxyl 54 Hydroxyl 65 Reduced viscosity in orthochlorophenol 0.80 Glass transition temperature, C. (differential thermal-analysis) 58 Pellets of polycaproamide having the following properties were employed:

Melting point, C. (differential thermal-analysis) 222 End group analysis in milli-equivalents per kilogram A mixture of 55 parts polyamide and 45 parts polyester pellets by weight was blended in a tumble blender for one hour. The granular blend was dried to a moisture content of no more than 0.033% and then melt blended at 274 C. in a 3 /2 inch diameter extruder operated at a rotational speed of about 18.7 r.p.m. to produce a pressure of about 3000 lbs. per square inch at the outlet. The temperature of the polymer composition on leaving the extruder was 275 C.

The molten mixture was pumped through a filter pack including a series of screens and a sand bed under a pressure of about 3500 lbs. per square inch at a temperature of 265 C. and was extruded through a spinnerette plate having 204 orifices of circular cross section each of said orifices having the following dimensions-length 0.069 inch, diameter 0.018 inch, entrance angle 20. The re- 'sulting filaments passed downwardly through a quenching chamber containing air at 27.8 C. and 65% relative humidity flowing cocurrently to the filaments at a rate of about 75 cubic feet per minute. The yarn was taken up onto a'cylindrical package below the quenching chamber at a speed of 1180 feet per minute under a tension of 35 to 45 grams. Just prior to packaging a lubricating finish was applied to the yarn to the extent of 4.5% pickup based on the weight of yarn. The yarn thus obtained had an approximate denier of 6666 and a birefringence of 0.0043.

The yarn was then subjected to a drawing operation by running the yarn to an upper draw roll from a cot feed roll to prevent yarn slippage. Then in one Wrap about a stationary ceramic drawpin of 1%. inch diameter, then to a contact surface heater at C. and finally in five wraps about a lower draw roll and associated at a peripheral speed of 5.48 times faster than the upper draw roll the yarn was drawn to 5.23 times its initial length.

The yarn was subsequently wound onto a pirn at a rate of 840 feet per minute using a ring-traveler device so as to impart 0.5 turn per inch twist to the yarn. The yarn thus obtained had the following properties:

Denier 1265 Ultimate Elongation, percent 14.5 Ultimate tensile strength, grams per denier 8.73

Breaking strength, grams 11,043 Tensile modulus, grams per denier 75 Shrinkage percent 12 The following phenomena were observed during the preparation of 1741 pounds of yarn:

Drips per hour at the spinnerette 0.375 Breaks per pound at the drawtwister 0.073 Wraps per pound at the drawtwister 0.114

1 1 EXAMPLE 6 The process of this example is substantially similar to that of Example 5 except that in this example 0.10% sodium stearate is employed as a spinning aid and the extruder is used to feed two positions. It should be noted in comparing the results that the drips per hour in Examples 5 and 6 are substantially the same. However, the throughput per hour in Example 6 is 65.4 lbs. per hour, whereas the total throughput in Example 5 is 32.7 lbs. per hour. It is thus apparent that the use of the spinning aid in accordance with this invention permits the spinning of polyester-polyamide blends at a much higher rate without adversely affecting the drips per hour, which heretofore has not been accomplished.

Pellets of polyethylene terephthalate having the following properties were employed:

Melting point, C. (diiferential thermal analysis) 250 End group analysis in milli-equivalents per kilogram of carboxyl 54 Hydroxyl 65 Reduced viscosity in orthochlorophenol 0.80 Glass transition temperature, C. (differential thermal analysis) 58 Pellets of polycaproamide having the following properties were employed:

Melting point, C. (ditferential thermal analysis) 222 End group analysis in milli-equivalents per kilogram of polymer carboxyl 70 Amino 17 Reduced viscosity in ortho-chlorophenol 1.04 Glass transition temperature, C. (differential thermal analysis) 48 A mixture of 55 parts polyamide and 45 parts polyester pellets by weight containing 0.10 part by weight of sodium stearate was blended in a tumble blender for one hour. The granular blend was dried to a moisture content of no more than 0.035% and then melt blended at 274 C. in a 3 inch diameter extruder operated at a rotational speed of about 30 r.p.m. to produce a pressure of about 3000 lbs. per square inch at the outlet. The temperature of the polymer composition on leaving the extruder was 275 C.

The molten mixture was pumped through a filter pack including a series of screens and a sand bed under a pressure of about 3500 lbs. per square inch at a temperature of 265 C. and was extruded through two spinnerette plates each having 204 orifices of circular cross section each of said orifices having the following dimensionslength 0.069 inch, diameter 0.018 inch, entrance angle 20". The resulting filaments passed downwardly through a quenching chamber containing air at 27.8" C. and 65% relative humidity flowing cocurrently to the filaments at a rate of about 75 cubic feet per minute. The yarn was taken up onto a clyindrical package below the quenching chamber at a speed of 1180 feet per minute under a tension of 35 to 45 grams. Just prior to packaging a lubricating finish was applied to the yard to the extent of 4.5% pickup based on the weight of yarn. The yarn thus obtained had an approximate denier of 6616 and a birefringence of 0.0043.

The yarn was then subjected to a drawing operation by running the yarn to an upper draw roll from a cot feed roll. It was then passed in one wrap about a stationary ceramic drawpin of 1% inch diameter, then to a contact surface heater at 135 C. and finally in five wraps about a lower draw roll and associated at a peripheral speed of 5.56 times faster than the the upper draw roll the yarn was drawn to 5.38 times its initial length.

The yarn was subsequently wound onto a pirn at a rate of 840 feet per minute using a ring-traveler device so as to impart 0.5 turn per inch twist to the yarn. The yarn thus obtained had the following properties:

Denier 1257 Ultimate elongation, percent 14.9 Ultimate tensile strength, grams per denier 8.89 Breaking strength, grams 11,181 Tensile modulus, grams per denier 79 Shrinkage percent 12 The following phenomena were observed during the preparation of 1741 pounds of yarn:

Drips per hour at the spinnerette 0.37 Breaks per pound at the drawtwister 0.093 Wraps per pound at the drawtwister 0.030

EXAMPLE 7 The following is a list of a variety of spinning aids which were employed in accordance with this invention utilizing a 30/70 blend of polyester and polyamide in which the polyethylene terephthalate and polycaproamide employed were similar to those utilized in Example 2 and were similarly processed to produce the yarn. In each case less than one drip per hour was observed.

Additive compound employed at a concentration of 0.2 part by weight Ethylene bis stearamide Methylene bis stearamide Ethylene bis behenamide N,N' (hydrazine) distearamide p-Phenylene bis stearamide 1,4- phenyl) stearate stearamide (p,p' Diphenyl ether) dipalmitamide (p,p Diphenyl methyl) distearamide (p,p Diphenyl methyl) dilauramide (p,p Diphenyl) distearamide Sodium stearate Sodium palmitate Barium stearate Calcium stearate Copper stearate Lithium stearate Magnesium stearate Zinc stearate EXAMPLE 8 A mixture containing 30% by weight polyethylene terephthalate and by weight polycaproamide, each polymer having properties similar to the polymers employed in Example 2 was blended together with varying amounts of sodium stearate dry powder in a tumbler cone blender for one hour. The granular blend was dried to a moisture content of no more than 0.038% and then melt blended at 265 C. in a 3.5 inch diameter extruder operated at a rotational speed of 23 r.p.m. to produce a pressure of about 3000 lbs. per square inch at the outlet. The temperature of the polymer composition on leaving the extruder was 265 C.

The molten mixture was pumped through a filter pack including a series of screens and a sand bed under a pressure of 2000 lbs. per square inch at a temperature of 265 C. and was extruded through a spinnerette plate having 204 orifices of circular cross section, each of said orifices having the following dimensions-length 0.069 inch, diameter 0.018 inch. The resulting filaments passed downwardly through a quenching chamber containlng air at 27.8 C. and 65% relative humidity flowing cocurrently to the filaments at a rate of about 58 cubic feet per minute. The yarn was taken up onto a cylindrical package below the quenching chamber at a speed of 1130 feet per minute under a tension of 35 grams. Just prior to packaging a lubricating finish was applied to the yarn to the extent of 4.6% pickup based on the weight of the yarn. The yarn thus obtained had an approximate denier of 6844 and a birefringence of 0.0025.

The yarn was then subjected to a drawing operation by running the yarn to an upper draw roll from a cot to prevent slippage. It was then passed in one wrap about a stationary ceramic draw pin of 1.5 inch diameter to a contact surface heater at 185 C. and finally in five wraps about a lower draw roll at a peripheral speed of 5.73 times faster than the upper draw roll. The yarn was drawn to 5.40 times its initial length.

The yard was subsequently wound onto a pirn at a rate of 840 feet per minute using a ring traveler device so as to impart 0.5 turn per inch twist to the yarn. Table III below' records the results obtained without sodium stearate and with sodium stearate at four different levels of concentration.

TABLE III Percent sodium stearate 0.0 0. 1 0, 3 0. 4 O. 6 Pounds spun. 6. 3 281 528 523 200 Drips/hn. 0. 98 0. 0. l9 0. 13 0. l Wraps/1b.- 0. 13 0. 0 0. 0 0. 0 0. 0 Breaks/lb 0. 086 0. 016 0. 015 0. 0055 0. 003 Denier 1, 258 1, 274 1, 265 1, 267 1, 263 Ultimate elongation, percent 15. 5 14. 8 15. 1 15. 2 15. 3 Ultimate tensile strength, grams per denier. L; 9. 75 9. 50 9. 46 9. 20 8. 55 Tensile modlilus, grams per denier 64. 6 68. 4 66. 9 67. 4 69. 1 Pounds drawn 207. 1 253. 6 326.0 361. 7 185 It has been established that the presence of the spinning aids employed in this invention does not adversely affect the properties of the products produced.

A test for the fiat spotting propensity of a given yarn is knownto correlate well with actual performance of yarns in tires reinforced-therewith. The details of the standard test procedure are as follows:

Conditioning the specimens:

(1) Suspend two 20-inch specimens of 840 denier yarn in an oven; (a glass tube jacketed for heating by steam) containing dry nitrogen.

(2) Apply a 0.5 g./d. load to each specimen and heat oven to 105 C.; hold temperature and load for one hour.

(3) Cool oven to room temperature and increase load to 0.75 g./d.; hold for 30 minutes.

(4) Heat oven to 105 C.; hold for one hour.

(5) Cool oven to room temperature; and hold for 30 minutes.

(6) Reduce load to 0.50 g./d. Heat oven to 105 C.; hold for 16 hours.

(7) Cool oven to room temperature and hold for 30 minutes.

The conditioned specimens are tested as follows:

(8) Heat oven to 105 C.; hold for 20 minutes.

(9) Reduce load on one specimen (yarn B) to 0.25 g./d. hold for 5 minutes, then cool oven to room temperature (approximately 20 minutes).

(10) Increase load on yarn B to 0.5 g./d.

Observe length of specimen after 30 seconds.

The fiat-spot index is taken as the differences in length between the twospecimens afterreapplication of load in step 10, expressed in millimeters and multiplied by ten. When tested in accordance with this procedure it was found that the fiat spot index of the yarn prepared utilizing 0.11% by weight sodium stearate was 22 and that the flat spot index for a yarn prepared with no sodium stearate was substantially the same. This figure is well within the range of commercial acceptability.

The adhesion test employed herein is the standard H adhesion test employing two-ply cords of the yarn to be tested, coated with the standard resorcinol-formaldehydelatex or a polyester adhesive finish, and employing natural rubber as the elastomeric substrate. In the test method, the force in pounds is measured for pulling, in the axial direction, one test cord from a laminate of rubber with a quarter inch length of cord embedded therein, said laminate being maintained at 250 F. In the preparation of the test laminate, the adhesive-treated cord is placed between two thicknesses of rubber stock in a mold with the cord under a tension of 50 grams. The sandwich assembly is then vulcanized in the press for 30 minutes at 280 F. under a 150 p.s.i.g. load. When tested in accordance with the foregoing procedure it was found that within the degree of confidence of the method the adhesion values of yarns prepared by the procedure of Examples 5 and 6 were equivalent.

What is claimed is:

1. A spinnable composition comprising a fiber forming polyamide having dispersed therein about 10 to 50 parts by weight of a fiber forming polyester together with from about 0.05 to about 0.6 part by weight of a wax-like spinning aid having a melting point above C., a mold release index of greater than 25 when incorporated in pure polycaprolactam and further characterized by the presence of a straight chain, saturated acyl group having from 12 to 22 carbon atoms in the hydrocarbon chain, all parts by weight being based on the total weight of the composition.

2. The spinnable composition of claim 1 wherein the Wax-like spinning aid is selected from the group consisting of an alkali or alkaline earth metal salt of an aliphatic carboxylic acid and a diamide derived by the reaction of an aliphatic carboxylic acid and a compound selected from the group consisting of a diamine and hydrazine.

3. A spinnable composition as defined in claim 2 in which the spinning aid is an alkali or alkaline earth metal salt of an aliphatic carboxylic acid.

4. A spinnable composition as defined in claim 2 in which the spinning aid is sodium stearate.

5. A spinnable composition as defined in claim 2 in which the spinning aid is sodium palmitate.

6. A spinnable composition as defined in claim 2 in which the polyester is fiber froming polyethylene terephthalate in the amount of from 10 to 50 parts by weight.

7. A spinnable composition as defined in claim 2 in which not more than 40 percent of the end groups in the polyamide are species which are reactive in the melt with the polyester.

8. The spinnable composition as defined in claim 2 in which the spinning aid is a diamide derived by the reaction of an aliphatic carboxylic acid and a compound selected from the group consisting of a diamine and hydrazine.

9. A spinnable composition as defined in claim 2 in which the spinning aid is calcium stearate.

10. In the process of spinning a composition comprising a fiber forming polyamide having dispersed therein about 10 to 50 parts by weight of a fiber forming polyester, the step which comprises addding from 0.05 to 0.6 part by weight of a wax-like spinning aid having a melting point above 100 C., a mold release index of greater than 25 when incorporated in pure polycaprolactam and further characterized by the presence of a straight chain, saturated acyl group having from 12 to 22 carbon atoms in the hydrocarbon chain, all parts by weight being based on the total weight of the composition.

11. A process as defined in claim 10 in which the waxlike spinning aid is selected from the group consisting of an alkali or alkaline earth metal salt of an aliphatic carboxylic acid and a diamide derived by the reaction of an aliphatic carboxylic acid and a compound selected from the group consisting of a diamine and hydrazine.

12. A process as defined in claim 11 in which the spinning aid is an alkali or alkaline earth metal salt of an aliphatic carboxylic acid.

13. A process as defined in claim 11 spinning aid is sodium stearate.

14. A process as defined in claim 11 in which the spinning aid is sodium palmitate.

15. A process as defined in claim 11 in which the polyester is polyethylene terephthalate in the amount of from 10 to 50 parts by weight.

16. A process as defined in claim 11 in which not more than 40 percent of the end groups in the polyamide are species which are reactive in the melt with the polyester.

in which the 15 16 17. A process as defined in claim 11 in which the 3,008,908 11/1961 Voigt 26018 spinning aid is calcium stearate. 3,260,689 7/1966 Kibler et a1. 26022 18. A process as defined in claim 11 in which the 3,280,053 10/1966 Twilley et a1 26018 spinning aid is a diamide derived by the reaction of an aliphatic carboxylic acid and a. compound selected from 5 FOREIGN PAP FE NTS the group consisting of a diamine and hydrazine. 2/1962 G t Brltaln.

Refer nces cited DONALD E. czAJA, Primary Examiner UNITED STATES PATENTS R. W. GRIFFIN, Assistant Examiner 3,039,895 6/1962 Yuk 117-1395 10 U.S. c1. X.R.

2,856,373 10/1958 Lowery et a1. 26018 3,002,942 10/1961 Zoetbrood 26022 117 13952618264"176 

